An nVidia GeForce GT220 graphics card, which costs about £30, is capable of cracking strong passwords in a matter of hours. Security experts were able to crack a 6 character password in 4 seconds, a 7 character password in less than 5 minutes, and 8 character password in four hours.

"People have worked out that the processing power of graphics cards, due to the architecture of the chips, is more powerful than a normal processor for doing certain tasks," said Neil Lathwood, IT director at UKFast.